How does a total beginner start to learn machine learning if they have some knowledge of programming languages?
It depends on what you want to use machine learning for. You can start by reading an introductory book on data science, just to understand what machine learning is and the differences between supervised and unsupervised learning. A very good introductory book to start with is, Numsense! Data Science for the Layman: No Math Added by Annalyn Ng and Kenneth So.
There are also a number of courses available on Edx and Coursera. My favourite one is Analytics Edge on Edx from MIT which teaches some of the basic skills needed for machine learning though it doesn't use the term machine learning. The course is taught using the R programming language (which is my favourite as opposed to python which is more common), but it uses some good practical examples to show how data science works. Microsoft and IBM also have basic machine learning courses in python on Edx.